A salutation is a greeting used in a letter or other communication. Salutations can be formal or informal. The most common form of salutation in an English letter includes the recipient's given name or title. For each style of salutation there is an accompanying style of complimentary close, known as valediction. Examples of non-written salutations are bowing, waving, or even addressing somebody by their name. A salutation can be interpreted as a form of a signal in which the receiver of the salutation is being acknowledged, respected or thanked. Another simple but very common example of a salutation is a military salute. By saluting another rank, that person is signalling or showing his or her acknowledgement of the importance or significance of that person and his or her rank. Some greetings are considered vulgar, others "rude" and others "polite".